1. Field of the Invention
The present invention relates to an internal combustion engine.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 62-191622 discloses an internal combustion engine having a fuel injector for injecting fuel directly into a cylinder. In this engine, an entire amount of fuel to be injected is injected during a latter half of a compression stroke when the engine is operating under low and medium loads, and a part of the amount of fuel to be injected is injected before and after bottom dead center (BDC) of an intake stroke, and the remaining part is injected during the latter half of the compression stroke, when the engine is operating under a high load. Namely, when the engine is operating under a high load, a prior injection is carried out before and after the BDC of an intake stroke and a subsequent injection is carried out during the latter half of the compression stroke.
When the engine is operating under a high load, however, since the prior injection is carried out from approximately the end of the intake stroke to approximately the beginning of the compression stroke, the period from a timing of the prior injection to a timing of an ignition is short, and therefore, fuel injected during the prior injection is not fully evaporated and not completely mixed with the air, and thus a problem arises in that a good combustion and a sufficient engine power can not be obtained.